A simple strategy to amplify specifically the HLA‐DQβ gene region with genomic DNA as template

Abstract
The nature of codon 57 in the HLA‐DQβ gene was recently reported as a potential marker of genetic susceptibility to insulin‐dependent diabetes mellitus. When exploring the relevance of this marker by using genomic DNA amplification, we encountered difficulties resulting from the coamplification of the homologous DXβ region. A simple strategy is proposed to amplify the DQβ region exclusively. It involves the preliminary digestion of genomic DNA with a restriction enzyme which cleaves DXβ specifically, leaving intact the DQβ sequence. The amplified material is suitable for dot blot analysis and restriction enzyme digestion. This strategy is of general interest when homologous sequences impair the specificity of enzymatic DNA amplification.